OSGI and start levels

Eclipse Plug-in start levels are there to simply determine the start order of bundles.
But as a developer or end user, we should never treat or code based on the order of OSGI start levels, it's completely managed by OSGI framework.

At least as of now, I have never come across the situation where I need to modify the plugin start level to launch an eclipse or develop Eclipse RCP Applications.

References:
http://eclipsesource.com/blogs/2009/06/10/osgi-and-start-levels/

http://aaronz-sakai.blogspot.in/2009/05/osgi-system-and-bundle-start-levels.html

http://www.osgi.org/download/r4v41/r4.core.pdf

http://help.eclipse.org/indigo/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fmisc%2Fruntime-options.html

From eclipse run time options:
The start-level indicates the OSGi start level at which the bundle should run. If the start-level (>0 integer) is omitted then the framework will use the default start level for the bundle.

If they do not specify a startlevel then they default to the value of osgi.bundles.defaultStartLevel. The default value of osgi.bundles.defaultStartLevel is 4